铸态AZ80镁合金高温热变形行为研究

Hot deformation behaviors of as-cast AZ80 Magnesium alloy at elevated temperatures

在Gleeble-1500热模拟机上对铸态AZ80镁合金在应变速率为0．005s^-1～5s^-1、变形温度为200℃～400℃条件下的高温热压缩变形行为进行了研究。结果表明，材料真应力-真应变曲线呈现动态再结晶特征。在温度T≥250℃，试样流变应力行为对应变速率敏感；在低温下T=200℃，应变速率对流变应力影响不大。高温下试样流变应力符合幂指数函数关系，应力指数n为6，热变形激活能Q为220kJ／mol。在高应变速率条件下，试样在变形中的温升是应变量的函数。实验中，Zener—Hollomon参数值大的试样温升明显，而Zener-Hollomon值小的试样变形温度基本保持不变。

Hot compression tests of as-cast AZS0 Magnesium 0. 005s^- ～ 5s^-1 and deformation temperature 200℃ ～400℃. alloy were performed on Gleeble 1500 at strain rates ranged between The results show that flow stress behavior is characteristic for hot working processes where DRX leads to work softening and strongly depends on the strain rate during high deformation temperatures （T≥250℃） except low temperature （T=200℃）. The relationships between flow stress and deformation temperature as well as strain rate can be represented by the exponential equation during deformation temperature over 200℃. The hot deformation activation energy Q derived from the experimental dates is 220 kJ/mol with stress exponent n= 6. The temperature rise caused by deformation at high strain rate is a function of strain and significant when Zener-Hollomon parameter is high.